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Experimental Studies and Simulation of Laser Ablation of High-Density Polyethylene Films by Sandeep Ravi Kumar a Thesis Submitte

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Experimental Studies and Simulation of Laser Ablation of High-Density Polyethylene Films by Sandeep Ravi Kumar a Thesis Submitte Experimental studies and simulation of laser ablation of high-density polyethylene films by Sandeep Ravi Kumar A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Industrial Engineering Program of Study Committee: Hantang Qin, Major Professor Beiwen Li Matthew Frank The student author, whose presentation of the scholarship herein was approved by the program of study committee, is solely responsible for the content of this thesis. The Graduate College will ensure this thesis is globally accessible and will not permit alterations after a degree is conferred. Iowa State University Ames, Iowa 2020 Copyright © Sandeep Ravi Kumar, 2020. All rights reserved. ii DEDICATION I dedicate my thesis work to my family and many friends. A special feeling of gratitude to my loving parents Ravi Kumar and Vasanthi, whose words of encouragement have made me what I am today. iii TABLE OF CONTENTS Page LIST OF FIGURES .................................................................................................................... v LIST OF TABLES ....................................................................................................................vii NOMENCLATURE ................................................................................................................ viii ACKNOWLEDGMENTS .......................................................................................................... ix ABSTRACT ............................................................................................................................... x CHAPTER 1. GENERAL INTRODUCTION ............................................................................. 1 1.1 Overview ..........................................................................................................................1 1.2 Thesis Organization ..........................................................................................................3 CHAPTER 2. LASER ABLATION OF POLYMERS: A REVIEW ............................................ 4 2.1 Abstract ............................................................................................................................4 2.2 Introduction ......................................................................................................................5 2.3 Laser Ablation ..................................................................................................................7 2.3.1 Mechanisms of Laser Ablation .................................................................................7 2.3.2 Ablation Parameters .................................................................................................9 2.3.3 Laser Source .......................................................................................................... 11 2.4 Polymer Material ............................................................................................................ 12 2.4.1 Polytetrafluoroethylene (PTFE) .............................................................................. 13 2.4.2 Polyimide (PI) ........................................................................................................ 15 2.4.3 Polydimethylsiloxane (PDMS) ............................................................................... 17 2.4.4 Polyethylene Terephthalate (PET) .......................................................................... 19 2.4.5 Polymethyl Methacrylate (PMMA) ........................................................................ 20 2.4.6 Other Polymers ...................................................................................................... 22 2.5 Applications of Laser Ablation of Polymers ................................................................... 25 2.6 Challenges and Future Scope .......................................................................................... 27 2.7 Summary and Outlook .................................................................................................... 28 2.8 References...................................................................................................................... 30 CHAPTER 3. AN AREA-DEPTH APPROXIMATION MODEL OF MICRO-DRILLING ON HIGH-DENSITY POLYETHYLENE (HDPE) SOFT FILMS USING PULSED LASER ABLATION .............................................................................................................................. 39 3.1 Abstract .......................................................................................................................... 39 3.2 Introduction .................................................................................................................... 40 3.3 Experimental Setup and Results ..................................................................................... 43 3.4 Data Analysis and Modelling ......................................................................................... 46 3.4.1 Effects of Number of Pulses and Power on Hole Depth .......................................... 46 3.4.2 Effects of Number of Pulses and Power on Hole Area ............................................ 48 3.4.3 Area-Depth Approximation Model ......................................................................... 49 iv 3.5 Conclusion ..................................................................................................................... 54 3.6 References...................................................................................................................... 55 CHAPTER 4. FINITE ELEMENT METHOD (FEM) BASED SIMULATION OF LASER ABLATION: SURFACE TEMPERATURE AND DEPTH PROFILE EVOLUTION ............... 58 4.1 Abstract .......................................................................................................................... 58 4.2 Introduction .................................................................................................................... 59 4.3 Materials and Methods ................................................................................................... 61 4.3.1 Simulation Model ................................................................................................... 61 4.3.2 Laser Procedure...................................................................................................... 62 4.3.3 Geometric Description of the Model ....................................................................... 63 4.3.4 Heat Transfer Description....................................................................................... 64 4.4 Simulation Results ......................................................................................................... 66 4.5 Future Work ................................................................................................................... 69 4.6 Conclusion ..................................................................................................................... 69 4.7 References ...................................................................................................................... 70 CHAPTER 5. GENERAL CONCLUSION ............................................................................... 72 v LIST OF FIGURES Page Figure 2.1 Laser-material interaction zone and input/output parameters.......................................7 Figure 3.1 (a) Experimental setup of laser ablation: opotek 3034 tuneable laser at 1064 nm wavelength, (b) Mechanism of laser ablation, and (c) Laser power tuned at different percentages of maximum power. ............................................................. 44 Figure 3.2 (a) 2D image of micro-drilled crater and (b) 3D profile of the micro-drilled hole, and (c) Cross sectional depth profile of micro-drilled hole for 5 pulses at 6.6% of maximum power................................................................................................ 45 Figure 3.3 (a-f).3D profile of the micro-drilled holes for (a) 3, (b) 7, (c) 9, (d) 11, (e) 20, (f) 30 pulses and 6.6% of maximum power. ................................................................ 46 Figure 3.4 (a) Depth of ablation (µm) as a function of the number of pulses at several different power levels, and (b) Depth of ablation (µm) as a function of the power level at several different numbers of pulses. ................................................ 47 Figure 3.5 (a) Area as a function of the power for a given number of pulses, and (b) Multiplication factor trend used to calculate the area of the crater. ......................... 49 Figure 3.6 (a) Standard gaussian laser intensity profile for one individual pulse, and (b) Visual depiction of the area and depth of laser ablation zones at 5 pulses and 6.6% of max. power. .............................................................................................. 50 Figure 3.7 Accuracy of the (a) Area and (b) Depth approximation of the simulation with respect to the experimental observations. ............................................................... 53 Figure 3.8 Procedure to establish area-depth approximation model for micro-drilling based on pulsed laser ablation given any new substrate material. ..................................... 54 Figure 4.1 Ramp function. ......................................................................................................... 62 Figure 4.2 Analytic function that can depict a pulsed laser system. ...........................................
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